Maybe someone can explain why the modulation scheme matters, instead of the frequency range. AM less sensitive to phase noise? Or is it that AM radio typically means some frequency range?
With AM, any noise is just, well, straight noise as AM is a straight amplitude signal.
FM is a phase modulation scheme, so random noise is largely discarded, as instead you have a phase tracker tracking frequency modulation.
Basically AM will always have noise, but because of how simple it is unless the frequency is being totally trampled on you can get * something* from it.
FM by contrast will have almost perfect tracking with very low audible noise in the output… right up until the PLL loses tracking and you lose it all.
Perhaps Switching in the inverters of the EV will generate harmonics that are in the 540-1700khz AM range. Pulses of current in a wire between inverter and motor radiate fields which are then picked up by AM radio antenna. Because AM is amplitude modulation it is more susceptible to interference by a signal on the same frequency, whereas an FM station uses a band of frequencies to encode the information instead of the magnitude of a carrier.
Guessing
AM and FM radio at least in the US refer to both the modulation and the frequency bands.
AM is 530 kHz – 1700 kHz, using 10 kHz spacing
FM is 87.9 MHz to 107.9 Mhz with 200kHz spacing.
IMHO, there are enough AM driver information stations that I would be upset when I eventually learned I couldn't receive them on a car with no AM radio. But it might take several years for that (especially if it's an EV; I'm not taking that into the mountains, probably)
Because being in a remote and sparsely served area is exactly the kind of place where it's vastly easier to ride your thumb to the nearest gas station and get a couple gallons of gas in an emergency than to arrange charging or a tow?
Why would you be out of gas in the mountains in the first place? Because you got snowbound and ran the car every couple hours to get some heat out of it.
Also ease of repairs in rural areas. Bubba’s Auto down the road probably has enough duct tape, clamps and experience to get most ICE cars semi-functional if they’re not totaled. A friendly home owner may even loan you tools to work on an ICE car.
Nobody in Bumfuck, Nowhere is going to have the tools or technicians to try to repair an EV. It will likely be a long and expensive tow to somewhere that does.
> Because you got snowbound and ran the car every couple hours to get some heat out of it.
Complete tangent, but how do EVs handle low-traction surfaces? Seems like they might do better on average from the weight, but that’s a wild guess on my part.
It depends on the programming and what tires you have. Electric motors have an enormous amount of instant torque which is exactly what you don’t want in a low traction situation.
The real danger on highways is traction control. It can hide how slippery the road is and allows you to easily outrun your braking ability.
In the northern Midwest, you’ll see car after car in the ditch when it hasn’t snowed in a while.
Early Priuses (Prii? Whatever) were notoriously crap on dirt roads because the traction control was too aggressive about cutting torque when the wheels started slipping, like even imperceptibly. On loose surfaces, you've got to allow some slip or you're unlikely to get anywhere, especially if it's uphill.
As for people forgetting how to drive in the snow over the summer? That seems to be universal. Seen it in Ohio, Massachusetts, Vermont, and New Hampshire.
modulation does not matter for range. however FM requires a greater signal strength to convey the information. if you are trying for distance, AM works with less recovered signal.
exclusive of digital modes, the most distance effective signal is CW. unmodulated signal, on or off.
FM uses 10 times the bandwidth and conveys more audio frequency range within it's signal than an AM one. FM has the benefit that building antenna gain is relatively easy so the Total Power Output of FM transmitters is often lower than for AM transmitters. You can generally expect to get 100kW Effective Radiated Power with only 20kW of input.
AM uses a significantly lower frequency and ground wave propagation is much more likely which gives AM the benefit of being able to reach "over the horizon" where FM simply cannot.
